1. Field of Invention
The invention relates to an apparatus for generating hydrogen. More particularly, the invention relates to an apparatus for generating hydrogen with a solid state reactant.
2. Description of Related Art
Fuel cells (FCs) are power packages capable of directly transforming chemical energy into electric energy. Comparing with the traditional method for generating electric power, fuel cells have the advantages of low pollutions, low noise, high energy density and high energy conversion efficiency. Therefore, the prospect of fuel cells as the non polluting source of energy is brightening. Furthermore, the fuel cells are applicable in various fields, such as a portable electronic products, a home power generation system, transportation, military equipment, space industry, a small-size power generation system, and so forth.
Specifically, various FCs could be applied to different fields based on different operational conditions. When the FC is used as a mobile energy source, the FC mainly refers to a hydrogen proton exchange membrane fuel cell (PEMFC) and a direct methanol fuel cell (DMFC). Both of them are operated at low temperature with use of the proton exchange membrane to perform proton conduction mechanism. Under the operation principle of the proton exchange membrane cell, such as the oxidation reaction of the hydrogen at an anode catalyst layer to generate hydrogen ions (H+) and electrons (e−) (PEMFC) or the oxidation reaction of the methanol and water at the anode catalyst layer to generate hydrogen ions (H+), carbon dioxide (CO2) and electrons (e−) (DMFC), the hydrogen ions could be conducted to the cathode through the proton exchange membrane while the electrons could be transported to the cathode after the electrons flowing through an external circuit are applied to a load to work. The reduction reaction between the oxygen supplied to the cathode and the hydrogen ions and the electrons occurs at a cathode catalyst layer, and thereby water is produced. The aforementioned hydrogen for the anode could be obtained from the solid state sodium borohydride (NaBH4) hydrogen storage technique in which the water is introduced into the solid state sodium borohydride to generate hydrogen.
For instance, the solid state sodium borohydride and water bag could be placed in a housing and the housing is equipped with a string object therein for piercing the water bag. The user could push the button on the housing for piercing the water bag so that the water in the water bag flows out of the water bag and reacts with the solid state sodium borohydride to generate hydrogen. When the leak of the water bag is not big enough, only a small portion of water flows from the water bag and most of water remains in the water bag. Therefore, the solid state sodium borohydride could not react with the adequate amount of water and the generation efficiency of hydrogen is low.
Taiwan Patent No. TW200640070 and the United State Publication No. US20090029209 and No. US20040243184 disclose the related arts of fuel cells.